Dual wheel drive with lubricating means



May 12, 1953 E. J. DUNHAM DUAL WHEEL DRIVE WITH LUBRICATING MEANS 3 Sheets-Sheet 1 Filed May 31, 1950 as 84 a3 May 12, 1953 Filed May 31, 1950 FIG. 2

E. J. DUNHAM DUAL WHEEL. DRIVE WITH LUBRICATING MEANS 5 Sheets-Sheet 2 V INVENTOR. ELMER a. DUNHAM May 12, 1953 E. J. DUNHAM DUAL WHEEL DRIVE WITH LUBRICATING MEANS 3 Sheets-Sheet 3 Filed May 51, 1950 INVENTOR.

ELMER J. DUNHAM Patented May 12, 1953 DUAL WHEEL DRIVE WITH LUBRICATIN G MEANS Elmer J. Dunham, Battle Creek, Mich, assignor to Clark Equipment Company,

Buchanan,

Mich., a corporation of Michigan Application May 31, 1950, Serial No. 165,333

4 Claims.

My invention relates generally to drive means and, more specifically, to a dual wheel drive having utility, for example, for industrial trucks.

It is an object of my present invention to'provide a dual wheel drive for a vehicle of the character noted, which may be utilized for steering as well as powering the latter.

l1 propose to accomplish this object by providing a vertically extending pinion shaft housing which, in a preferred adaptation of my invention to an industrial truck, is adapted to be rotatably mounted on the main frame of the truck, adjacent the rear end thereof. The pinion shaft housing at its upper end carriesa gear casin which is closed by a suitable cover member, and a pinion shaft is journaled in the pinion shaft housing with its upper end projecting into the gear casing. A prime mover is carried by the cover member and has an output shaft which extends into the gear casing. The upper end of the pinion shaft carries a gear which has meshing engagement with a gear on the output shaft of the prime mover for effecting rotation of the pinion shaft by the prime mover. A drive axle housing is disposed at the lower end of the pinion shaft housing and provides for the journaled support of a pairbf coaxially aligned laterally extending drive axles. A conventional differential mechanism is disposed within the drive axle housing for effecting driving connection between a drive pinion, at the lower end of the pinion shaft, and the pair of drive axles. A pair of drive wheels are mounted'to the outer ends of the drive axles.

The prime mover, cover member, gear casing, pinion shaft housing, and drive axle housing are adapted tobe rotated as a unit and, thus, when a suitable steering handle is mounted thereto, may be utilized for steering a vehicle.

By providing a differential mechanism between the drive pinion andthe drive axles, one of the drive Wheels may rotate faster than the other when a turn is being initialed, which reduces the effort that must be expended by an operator of a vehicle, to which my present invention is attached, when maneuvering the latter.

It is another object of my present invention to provide a dual wheel drive in which the aforementioned gear housin pinion shaft housing, and differential housing are arranged in vertical relation, which arrangement is effective for reducing the overall length of a vehicle to which m invention is adapted to be attached. a

It is still another object of my present invention to provide a dual wheel drive having drive axles of a minimum axial extent.

I propose to accomplish this object by fabricating the drive wheels with hub portions having radially extending flanges to which, at the outer edges thereof, are formed axially inwardly extending rims. The axially inwardly extending rims, which may carry suitable tires, are adapted to overlie the outer ends of the tubular axle arms of the differential housing and are adapted to be mounted closely adjacent the vertically extending pinion shaft housing, which thus serve to reduce the axial extent of the drive axles to a minimum.

It is a further object of my invention to provide a lubricating system for lubricating the gears and bearings of the dual wheel drive.

I contemplate the provision of a fluid passageway in the upper end of the pinion shaft, which passageway opens radially to the outer periphery of the pinion shaft for lubricating the: latter. Fluid under pressure is transmitted to the passageway from a pump mounted in the differential housing, through a suitable fluid hose line having connection with a fluid passageway formed in the cover member, which passageway opens above the,

fluid passageway in the pinion shaft. Mounted to the upper end of the pinion shaft is an upwardly facing bell-shaped washer adapted to receive fluid which overflows from the fluid passageway in the pinion shaft. Disposed about the bell-shaped washer is a bracket which is secured to the cover member. The bracket has a trough which is adapted to receive fluid which overflows from the bell-shaped washer and direct the fluid to the point of contact between the pinion and gear disposed within the gear casing. All excess fluid runs down the outer periphery of the pinion shaft to the bottom of the differential housing, where it is received by the pump and recirculated.

It is a still further object of my invention to provide a lubricating pump which is driven from the differential case disposed within the differential housing.

I have provided a pump comprising a cylinder and a piston movable thereon, which piston has pivotally mounted at it outer end a follower normally biased into engagement with a cam groove formed in the outer periphery of the differential case. When the differential case is rotated the follower and piston are reciprocated and the pump then circulates lubricating fluid.

Now, in order to acquaint those skilled in the art with the manner of constructing and using devices in accordance with the principle of my present invention, I shall describe in connection with the accompanying drawings a preferred embodiment of my invention.

In the drawings:

Figure l is a side elevational View of the dual wheel drive of my present invention, with portions being broken away and shown in section and elevation;

Figure 2 is a vertical sectional view of the dual wheel drive of my present invention, taken substantially along the line 2-2 in Figure 1, looking in the direction indicated by the arrows; and

Figure 3 is a partial plan View of the dual wheel drive shown in Figure 1.

Referring now to the drawings, there is shown the dual wheel drive of my present invention which, as will be described in detail herein-.-

after, is rotatably mounted within a frame member Ill. The frame member H] is adapted to be secured to a vehicle as, for example, an industrial truck. The dual wheel drive of my present invention is not only adapted to drive the vehicle to which it is mounted, but alsoto steer the latter. Rotatably journaled within the housing is, by means of a ball bearing assembly I! adjacent the upper end thereof, and a plurality of needle bearings I2 adjacent. the lower end thereof, is a vertically extending tubular pinion shaft, housing l3. Rotatably journaled in, the tubular pinion shaft housing It, as by means of a tapered roller bearing assembly l4 adjacent the upper end thereof, and a tapered roller bearing assembly l5 adjacent-the lower end thereof, is a pinion shaft iii. Secured to the pinion shaft [6 adjacent the lower end thereof is a bevel drive pinion It, provided for a purpose to be described more fully hereinafter.

Mounted to the pinion shaft housing l3 adjacent the upper end thereof, as by means of a key I8, is a horizontally extending gear casing I 9. The gear casing l9, at its lower end, is

' adaptedv to bear against the inner race of the roller bearing assembly H, and is held in this position by means of a nut 2G threaded on the upper end of the pinion shaft housing [3. Secured to the upper edges of the gear casing 19, as by a plurality of bolts 29, is a cover member 22-.

Disposed within the gear casing i9 is a horizontally extending gear 26 which is mounted to the splined upper end of the pinion shaft It. The lower portion ofthe hub of the gear bears; against the upper portion of the inner race of the tapered roller bearing assembly l6 and is held in this position by means of, a. nut 21 threaded onto the upper end of the pinion shaft it; interposed between the gear 26 and the securing nut 22? is an upwardly facing bell.- shaped washer member 23. Disposed concen-. trically about the bell-shaped washer Z8 and secured to the cover member 22, as by a plurality or circumferentially spaced bolts 25), is a bracket member having an oil collecting trough 3| which extends forwardly, as shown at3 2 in Figure 1.

, Secured to the upper exterior surface of the cover member 22 is the lower end of-a vertically extending prime mover, indicated generally by the reference numeral 33, having an output-shaft 34;. which extends vertically downwardly intothe 35 has meshing engagement with the aforedescribed gear 26 secured to the upper end. of the pinion shaft it; that suitable driving connection isefifectedabe- It will thusbe observedtween the output shaft 34 of the prime mover 3t and the pinion I! on the pinion shaft [6, by means of the gears 36 and 2t.

Formed integrally with the pinion shaft housing I3, adjacent the lower end thereof, is a cylindrical portion 16 to which is secured by means of bolts 9%, laterally outwardly extending tubular arm portions 42 and 43. Rotatably journaled in the tubular axle arm 42 adjacent the outer end thereof, as by means of a tapered roller bearing assembly M, is the reduced end portion of a hub 45 of a differential bevel ring gear 58 which has meshing engagement with the aforedescribed bevel pinion ll.

Rotatably mounted in the tubular axle arm il-i, as by means of a tapered roller bearing assembly M, is the reduced end portion of a hub 48 of a differential case 49 which extends coaxially of the differential bevel ring gear 46.. The differential case 49 is suitably secured at its inner end, by means of a key 49 to the differential bevel ring gear 45 for rotation there-, with.

Disposed within the differential case 49, is a. differential spider assembly, indicated generally by the reference numeral 50;. The differential spider assembly 5i comprises a pin 5t which extends. radially across the, differential cas 9 and is. secured at its ends therein. Journaled on the pin iii are a pair of differential bevel pinions 52 and 53 which are, radially spaced by means of a, collar member 54 disposed about the pin 5i.

Rotatably journaled in the hub portion 45, of the differential bevel ring gear 48,, by means of a plurality of needlebearings 51,, is a drive axle 58 which extends. laterally outwardly therefrom. secured to the inner end of, the drive axle 5.8 is a differential side gear 59 which has meshing engagement with the aforedescribed differential bevel pinions 52 and 53.

Rotatably journaled. in the hub portion. 48 oil the differential case 49,. as by means of, a. plurality, of needle bearings 60, is a drive axle 6|; which extends laterally outwardly therefrom, coaxially of the drive axle, 5,8. Secured to the inner end of the drive axle BI is a differential bevel side gear 52 which hasv meshing, engagement with the aforedescribed, difi'erential, bevel pinions 5-2 and 53.

Keyedto the outer tapered, endsof each of the, drive axles 58, andl'il are thehub portions, 54. of drive wheels 65. Formed integrally with the hub portions 5.4; are radially extending flanges 62 which. have formed at their edges axially, inwardly extending rims 66. The rims. E 6.ov,erlie the outer ends. of the axle, arms. 42v and 43. for providing a dual wheel, drive, 0t minimum axial length. Solid. tires. 13. are mounted, on the outer periphery. of rims 66. The wheels: 65 are held on the tapered ends. of the drive axles 58 and ti by means of nuts 61 threaded! on. the ends of, the drive axles 5,8 and 6!. Each of the wheels 65' is formed with an axially inwardly ex: tending circumferential flange fiii'which projects inwardly of: the tubular axle" arms 4'2, and t3. Disposed between the outer periphery of the, flanges 58 of the wheels 55, and. the inner pee riphery. ofthe tubular axle-arms 42-;and 43, ad-. jacentsthe ends thereof,,are oilsealassembliesill.

From the. foregoing; description it will be observed that driveis efiectedifromthebevel pinion I ,ito the wheels-,65, through: the differential; bevel ring gear tt, differential casing 49; differential spider assembly 50;,andj the drive:v axles 581 and 6|. When both .of the wheels 65 are headed in a straightforward direction, the differentialpinions 52 and 53 do not rotate on the pins 5|, but serve only to :lock the elements of the spider assembly 50 together causing the differential casing 49 and sidegears 59 and 62 to rotate asa unit when the differential bevel gear 46 is rotated by the bevel pinion l1. When the elements of the spider assembly 50 rotate as a unit both of the wheels 65 rotate at the same speed. Upon initiating a turn, the inner Wheel 65 places a drag on the corresponding drive axle 58 or 6!, thereby decreasing the rotation of the latter and the corresponding side gear 59 or 82, with respect to the differential ring gear 46 and the differential casing 49. The differential case 49, through the pin 5|, then forces the differential pinions 52 and 53 to rotate along the inner side gear 59 or 62, advancing the opposite side gear 59 or 62 an equivalent amount with respect to the differential case 49. The outer Wheel 65 thus turns at a higher speed than the inner wheel 65.

Extending rearwardly from and preferably formed integrally with the cylindrical housing portion 18' is a bracket 70 to which is adapted to be pivotally mounted at H and 12 an upwardly extending steering handle. When the bracket is rotated by means of the steering handle (not shown) the tubular arm portions 42 and 43 are rotated, together with the pinion shaft housing l3, gear casing 19, cover member 22, and the prime mover 33. The drive unit is thus rotated as a unit, while drive is being transmitted to the wheels 65.

In order to effect adequate lubrication of the bearings and gears of the drive unit, there is disposed within the drive axle housing ll a pump assembly, indicated generally by the, reference numeral 15, which is suitably mounted in the bottom portion of the cylindrical housing portion 16. The pump assembly comprises a cylinder 16 in which is disposed for reciprocating motion a piston or plunger 11. The plunger 11 has rotatably journaled at its outer end, about an axis extending transversely thereof, a follower wheel 18 which is adapted to engage a cam groove 19 formed in the outer periphery of the differential casing 49. The follower 18 is biased into engagement with the cam groove 19 by means of a spring 80 disposed between the closed end of the cylinder 18 and the bottom portion of the plunger 11. l

Lateral inlet and outlet openings 8| and 82 are formed in the side wall of the cylinder l6 adjacent the closed end thereof. The inlet open with a vertical fluid passageway 89 which opens above a fluid passageway 98 formed in the upper end of the pinion shaft [6. The fluid passageway 98 opens into a radially extending fluid passageway 9! which opens outwardly of the pinion shaft l6 above the tapered roller bearing assembly M for lubricating the latter.

Rotation of the differential case 49 causes the follower l8, together with. the plunger ll, to

reciprocate within the cylinder 16 of the pump assembly '15. This reciprocatory motion of the plunger 11 cyclically draws oil into the cylinder 16 through the inlet opening 8 I, the fluid passageway 83, and the inlet opening 86 in the fluid passageway 83, from the reservoir provided at the lower portion of the cylindrical housing portion 16. Also, cyclically, oil is discharged from the cylinder 18 of the pump assembly 15 through the outlet opening 82, into the fluid line 8i. From the fluid line 81, the oil is directed under pressure to the fluid passageway 88, fluid passageway 89, andinto the fluid passageway 90 formed in the pinion shaft l6.

The excess oil directed into the fluid passageway 98, formed in the pinion shaft l6, overflows the upper end ofthe fluid passageway 90 and flows into the bell-shaped Washer 28. When the oil has filled the bell-shaped washer 28, it overflows into the oil channel 3| where it is directed, by means of the projecting portion 32, to the position of engagement between the pinion 38 and the gear 26 disposed within the gear casing H).

The excess oil delivered to the pinion 36, the gear 26, andthe tapered roller bearing assembly [4, runs downwardly along the outer periphery of the pinion shaft l6 within the pinion shaft housing I3 under the force of gravity. This excess oil lubricates the tapered roller bearing assembly l5 adjacent the lower end of the pinion shaft 16, the pinion H, the differentialring gear 4", the differential pinions 52 and 53, and the side gears 59 and 62. The excess oil fromthese elements of the drive unit runs downwardly under the force of gravity into the reservoir provided adjacent the lower end of the cylindrical housing portion 16'. From the reservoir the oil is again recirculated by means of the pump assembly .15.

While I have shown and described what I believe to be a preferred embodiment of my present invention, it will be understood that various modifications and rearrangements maybe made therein without departing from the spirit and scope of my present invention. i

I claim: l

1. A dualwheel drive comprising, a vertically extending pinion shaft housing, a pinion shaft rotatably mounted therein, a gear casing secured to the upper end of said pinion shaft housing, a gear disposed in said gear casing mounted to the upper end of said pinion shaft, means for rotating said gear, a cover member secured to said gear casing, a fluid passageway in said pinion shaft opening at the upper end of the latter and at the outer periphery of the latter, said passageway being adapted to direct fluid to the outer periphery of said pinion shaft for lubricating the latter, a fluid passageway in said cover member opening at its one end above said fluid passageway in said pinion shaft, a drive pinion secured to the lower end of said pinion shaft, a drive axle housing secured to the lower end of said pinion shaft housing, a differential mechanism comprising a differential case disposed in said drive axle housing, a cam groove formed in the periphery of said differential case, a lubricating pump mounted in the drive axle housing, said pump comprising a cylinder, a piston movable therein, a follower pivotally mounted to the end of said piston and biased into engagement with said cam groove whereby said follower and said piston are reciprocated when said differential case is rotated, means for conveying fluid from said pump to said fluid passageway in said cover member, horizontal coaxially aligned drive, axles sees, me

mounted for rotation in said driveaxle housing, said di fiferential mechanism efiecting d rivfi g actionbetween said drive pinion and said drive axles-, Wheels mounted to the outer ends or said drive axles.

2. A dual Wheel d'rivecomprising, a vertically extending pirli'on shafthousing, a pinion shaft rotatably mounted therein, a gear casing secured to the upper end of said pinionshaft housing, a gear disposed in said gear easing mounted to the upper end of said pinion shaft, a cover member secured to said gear casing, a prime mover eured to' said cover member having an output shaft extending into said gear casing; a pinion disposed said gear casing mounted onthe end of said output shaft; said pinion havi'ri'g meshing engagement with said gear, 'afluid passa'g'ev'v'ay in said pin-ion shaft openingat'tlie upper end of the latter and at the outer periphery ofthe latter, said passageway being adapted to direct fluid to the outerperiphery of said pinion shaft for lubricating the latter, a fluid passageway in said cover member opeuiiig at its one end above saidfluid passageway in said pinion shaft, same pinion secured to the lower end of said 'pii-iioi-i shaft, a drive axle housing secured tothe rower end of said pinion shaft housing, a differ-- ential mechanism comprising a difiere'nti'al case disposed in said drive axle lie-using, a cam groove formed inure peripheryof said di filel'ltlal case,

a lubricating pimp mounted in the drive axle housing, said pump comprising acy'lind'er, a piston movable there'i-n, a follower pivotally' mounted to the end of said pistonand biased into fl-f gagement was said cain groove whereby said 1';

foil Wer and said pi's'ton' are reciio-rocated when said differential case is rotated, means for coir-- veym-g sum from said pump to said fluid passage way in said cover member; upwardly facing b'elll shaiied washer secured to" the "ni'" shaft-fer coll" said fluid pass shaft, a bracket member disposed consent 1y about said bell-shaped washer secured to said cover member, said bracket member having a: fluid collecting trough which extends to the point of; contact between said pinion and said gear in said: gear casing, said fluidv collecting trough. adapted to collect fluid which over= flows: saidbell+shaped washer and direct the latter to said. pinioir and said gear for lubricatsaid drive axles, and; wheels mounted tothe outer ends of, said, driveaxless dual; drive Wheel comprising, a vertically extending: pinion shaft housing, a pinionv shaft rotatably mounted therein, a gear casing: secured to: theup'per end of said pinion shaft housing, a gear disposed in: said gear casing mounted. to the upper end of saidpi'niou shaft;v means for rotat gear; a. cover member secured to said ca ing, a fluid passageway in said pinion shafit oiie'riihg at theuie'pelend of the latter and at the outer periifihery of the latter, said passageway being adapted to direct fluid to the outer periphery of said pinion shaft" for' lubricating the latter, a fluid passageway in said cover member opening at its one end above said passagewaym said pinion shaft, a drive ifiinio'n secured to the lower end of said pinion shaft, a drive axle housing secured to the lower end of said'piziion shaft housing, a difierentialmecha-- ni'sm comprising" a di-fierential case disposed in said drive axle housing; a cam' groove formed in the periphery of said diiferential case, a In, bricatihg pump mounted in the driveaxle hous ing', said pump-being. actuated by said cam groove upon rotation of said differential ses me-ans for conveying fluid from said pump to saidfluid passageway saidoover member, horizontal coaiii'ally aligned drive axles mounted for rota= said drive axlehousing, said di fi'erehtial m s anismeffecting-drivingeo'nnectien between said vepinioh and said drive axles, and' wheels mounted isthe outer endsoi said drive axles.

r. dual drive Wheel comprising, a vertically extending pinionshaft housing, a pinion shaft rota-tabl'y'inounted therein, a gear easing secured to the upper end of'sai-d pinion shaft housingia gear disposed in said gear casing mounted to the upper end of saidpinion shaft, a cover mam be'r secured to said gear casing, a prime mover secured to said cover member having an' output shaft extending into said gear (raising; a pinion disposed in said gear casing mounted on the end of said output shaft, said pinioir having meshing engagement with said gear, a fluid passageway said pinion shaft opening at the-upset! end of the latter and at the outel' periphery or the letter; said passageway beiihg'adapted to direct fluid e the outer periphery of'said piuiea shaftfor were eating the latter; a fluid passageway said cover member opening at its one end abovesaid-fluid passageway irr pinionshaft, a drive pause secured to the lower end or said pinion shaft, a drive axle housing secured to the lower end or said pinion shaft housing; a differential mechanism comprising a diffei-ential ease disposed in said drive axle housing, acam groove fiormed n the periphery of saiddiff'erentia-lcase, a lubricat= in pump mounted in the drive 'a xl'e housing, said su 13' being actuated by said cam groove upon rotation oi said differential case, means for coirvey-ing-fiuid from-said pump to said fluid passageway insaid cover member, upwardly racing bell-shaped washer secured to the upper endof saidpi'ni'on shaft for collecting fiuid which everflows from said fluid passageway in sai' p 1 ion shaft, a bracket member disposed concentrically about said bell shaioed washer and secured to-said cover member; said bracket member having a fluid collecting trough extends tothe' point of contact between said pinion and said gear said gear casing, said fluid collecting trough being adaieted to collect fluid which overflows from said bell shaped Washer direct'the latterto said pinionand said gear for lubricating the latter, horizontal coaxi'auyaii'gn'ed drive axles mounted for" rotation in said drive axle housing; saididiffere'ntial mechani'sm'eiiecting, driving connection between said drive pinion and said drive axles, and wheels mounted to the outer ends of said drive axles;

EEMER J DUNHANI.

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